\begin{tabbing}
(\=(((((RepD) \+
\\[0ex]CollapseTHENM (OnVar `as' D))$\cdot$) 
\\[0ex]CollapseTHENM (Reduce 0))$\cdot$) 
\\[0ex]
\\[0ex]CollapseTHEN ((Auto\_aux (first\_nat 1:n) ((first\_nat 2:n),(first\_nat 3:n)) (first\_tok :t
\-\\[0ex]) inil\_term)))$\cdot$
\end{tabbing}